The invention relates to a method for removing nitrate ions from a solution, in particular from a spent decontamination solution or from another spent solution for reducing radioactivity.
Nitrate ions are not desired in wastewaters. They are, however, present in various solutions which are to be disposed of as wastewater. For example, spent decontamination solution which has been used in a nuclear power station for decontaminating surfaces comprises nitrate ions. The same is true of a solution which has been used for other methods of reducing radioactivity. In such processes, nitric acid, for example, is used, which releases nitrate ions in the solution.
It has already been proposed to use anion exchanger resins to remove nitrate ions from a solution. Such a process is very cost-intensive and gives rise to nitrate-charged ion exchanger resins, which have to be disposed of. In some areas of the technology, e.g. in nuclear technology, the charging of ion exchanger resins with nitrate ions is undesired since it is feared that amines already present in the ion exchanger resin will react with the nitrate ions.
It is accordingly an object of the invention to provide a method for removing nitrate ions from a solution which does not require ion exchangers and completely removes even the smallest concentrations of nitrate.